Hi spuluka-san,
As my understanding regarding the feature of [partition] option is,
1.Content that you showed
2.Can upgrade or downgrade both partitions at once.
Regarding No.2.
I know that that by using the command [request system snapshot slice alternate], can copy primary image to backup partition after performing command [requests system software add] without [partition] option.
I had just only tested for [partition] option.
However, this option did not working.
Regards,
GENC